Patent GB-609423-A (GB)
Title: Improvements in and relating to pneumatic despatch systems
IPC: B65G51/26
Filed: 1946-03-13
Abstract: 609,423. Air-lock for pneumatic tube transmission. LAMSON ENGINEERING CO., Ltd. March 13, 1946, No. 7910. Convention date, June 6, 1942. [Class 78 (i)] The pneumatic tube at a sending or receiving station is provided with a slide valve, e.g. discs 1, 2 of Fig. 1, actuated by a motor M which is automatically started by the passing of a carrier through the tube, the valve acting as an air-lock in the tube for the insertion or removal of a carrier without there being any direct communication between the atmosphere and the part of the tube in which there is a vacuum or a pressure, a system of stop members, e.g. 5, 6, 7, being also provided. which cooperate with the valve mechanism in the tube to regulate the movement of the carriers. Fig. 1. Motor M drives shaft 3, which rotates valve discs 1, 2, which pass hermetically through slots cut through air tube 4, and also cams 5a, 6a, 7a, which displace stops 5, 6, 7 in the tube by means of the frames shown. Current to motor M from supply E passes either through switch 13, operated by cam 15 or through switch 12, closed by lever 14 pivoted inside the tube. Operation.-Carrier falls down tube 4, tips lever 14 to start motor and to rotate shaft 3, and falls on to stop 6. Cam 5a then causes stop 5 to move into tube so as to hold up oncoming carrier. Lever 14 falls back to break switch 12, but current and shaft rotation continues now through switch 13 closed by cam 15. Slot 1a of disc 1 passes beneath tube 4 and retraction of stop 6 (by cam 6a) allows carrier to fall into air-lock 4a on to stop 7. Stop 6 then moves back into the tube and disc 1 now closes the tube. Slot 2a in disc 2 rotates to position beneath the tube, stop 7 is retracted and allows carrier to be discharged. Disc 2 now closes the tube and stop 7 and stop 5 returns to the normal position shown. A similar operation takes place when the carrier is received into the station. Another stop, as shown at 33, Fig. 7, may be inserted in the main pneumatic line and regulated by cam 33a, operated from shaft 3 so as to hold up a main line carrier and prevent it from colliding with a carrier departing from the above end station (shown at 4a). A byepass D<1> is provided for the main current of air. Fig. 8. If 24a and 24b are receiving and despatching stations, and 24c and 24d are the pneumatic tubes leading to these stations, then a drum 25 may be interposed with connecting tubes 20, 21, 22, 23 and mounted on shaft 26 so that by rotation of the drum through a quarter revolution the connections may be reversed. If tube 24d is blocked, this enables 24c to be used for both despatch and receipt of carriers. The drum is driven by motor M1 and controlled by cam 27. The latter may work pilot lamps to indicate the reversal of traffic. Fig. 2. An air-tight fit is ensured between disc 1 (or 2) and pneumatic tube 4 by fitting the latter with a resilient sleeve 16, which is pressed against the disc 1 by spring 17. By varying the gearing of motor M and therefore the speed of rotation of shaft 3 it is possible to vary the interval between the arrival or departure of successive carriers.